Coffer and method of making the same



April l2 1927.

B. C. GERWICK v COFFEE A-ND METHOD 0F MAKING THE SAME s sheets-sheet 1 'Filed Feb. 20. 1924 .lf. a: ab,

u, .A .n u s HIJ' arrvfrvf) April 1,624,330 B. c. GERwlcK COFFEE AND METHOD 0E MAKING THE SAME Filed Feb. 2o, 1924 5 Sheets-Sheet 2 1,624 330 APH! 12 1927' B.- c. GERwlcK COFFER AND METHOD OF MAKING THE SAME Filed Feb, 20, 1924 3 Sheets-Sheet 5 Patented Apr. 12, 1927.

UNITED STATES 1,624,330 PATENT OFFICE.

BEN C. GEB/WICK, OF BERKELEY, CALIFORNIA.

i l l COFFEE AND METHOD OF MAKING THE SAME.

Application filed February 20, 1924. Serial No. 694,001.

The invention relates to a coffer or other subaqueous structure for. excluding water and other materials from a confined area` The invention also relates to a method of making large coffers.

It. has been the practice heretofore, in building piers and other structures in water or in flowing mud, to use the plenum air or pneumatic caisson or to sink a surrounding open caisson, crib or colferdam of earth, timber, steel, concrete, or combinations of these materials, to exclude water and other materials fioin the surrounded space, to perinit the structure within vthe space to be built. The pneumatic system of operation is expensive, is detrimental to the health of the workmen and Ais of such character, that where wooden piles have to be driven to forni the foundation for the structure, almost insurmountable difculties are met. The pneumatic system also limits the depth to which the structure may be carried, due to the air pressure which can be sustained by the workmen. Open cribs, caissons and cofferdams have heretofore presented many troubles of bracing and unwatering, it being practically impossible to make the open cofferdams sufficiently tight so that they may be unwatered to any great depth.

IVhen the structure to be built is large, requiring a large cofferdam or caisson7 the weight of such caisson or cofferdam is so great that it cannot be handled. This is particularly true when the structure is to be built in shallow water overlying deep mud, the shallowness of the water precluding floating a caisson, or crib into place. Cui rents and tidal flow also present obstacles tothe iioating of a pre-cast or pre-built crib` or caisson into place and also interfere with the maintaining of alinement of the caisson, as it is being sunk.

An object of the present invention is to provide a cofl'er which overcomes the above mentioned difficulties and which may be built in any desired size to enclose any desired area.

Another object of the invention is to provide a coffer which possesses inherent re` sistance to external pressure, so thatl the necessity of internal bracing is eliminated.

Another object of the invention is to provide a. method of building a large cofl'er whereby no unusual oi large weights require handling or lifting.

A further object of the invention is to provide a method of building a large colfer in vertical sections.

The invention possesses'otlier yadvantageous features, some of which, with the fore going', will be set forth at length in the following description, where I shall outline in full that form of my invention which I have selected for illustration in the drawings accompanying and forming part of the present specification. In said drawings I have shown one form of cofl'er embodying my invention and in the specification I have described one method of making the coi'l'er, but it is to be understood that I do not limit myself to such form or method, since the invention, as set forth in the claims,

may be embodied iii a plurality of forms and constructed by a plurality of methods. Referring to said drawings: 1 Figure l is a vertical section through the completed cofferv of my invention, showing one for-in of structure arranged within the coffer. y

Figure 2 is a top or plan view of the completed coffer and structure shown in Figure l.

Figure 3 is a detail of one of the concrete shafts forming part of the cofl'er, a' port-ion of the shaft being broken away to disclose the anchor for one of the walls connecting tivo adjacent shafts.

Figure 4 is a detail of a portion of the .coffer showing various parts ofthe cofl'er in different stages of construction.

The cofferr` of my invention comprises generally a plurality of spaced concrete shafts built in situ and extending from above the water line to the established `grade. V D

the shafts are connected together by con- `crete walls built in situ, which' close vthe spaces between' the shafts, thus'forming an integral structure in which the shafts may be considered as abutments for receiving the strain placed on the walls. The'centers of the shafts are preferably arranged on a curve, usually a circle, so that the line of shafts surround the area to be unwatered. The walls connecting the successive shafts are also preferably curved and, when the shafts are arranged in a circle, thewalls are concentric with the center of the circle. Vvlhen the shafts are arranged in a straight line, the walls are curved to form arches, so that the stresses applied to the wallsaie transferred to the shafts, which act as abut- Incnts. It is not necessary that the shafts be i female edges.

Y arranged in a circle since, when the cofl'er is to enclose an area, the coifer may be elliptical or otherwise curved. 'Ihe walls presenttheir convex face to the surrounding` water and mud which is held baci: by the coffer, and by completely surrounding the area with the coffer, the coffer is self-supporting, and requires no internal bracing.

I prefer to build the coifer in successive vertical sections, progressing around the area to be enclosed, so that no large or unusual weights are required to be handled. In carrying out the invention, a steel cylinder or shell 2 is set in position and sunk to the established grade, either by digging out the interior or by driving the shell. The upper edge of the shell extends above the water line, when the shell has been sunk to the established grade, so that water will not enter the shell. After the shell has been sunk to the established grade, the mud, sand or other niaterial'within the shell is removed and a base t is then formed in the bottom of the shell.v When desirable, piles 5 may first he driven before the base is placed and these wooden piles 5 may readily be driven lin the bottom of the cylinder by using eX- tension leads on the pile driver. The concrete hase -1 is then formed, either by placing,- the concrete under water with a tremie, or by first unwatering the cylinder and placing the concrete in the usual manner. After the base has been formed a shaft form 6 is arranged within the cylinder and preferably concentric therewith, and concrete is poured into the form 6 to produce the concrete shaft 7. The successive shafts, after they have been formed and after the cylinders 2 have been removed, are connected together successively by a pair of spaced walls 8 formed of sheet steel piling 9. The forms G are provided on opposite sides, adjacent the succes-- sive shafts, with anchors l2, extending through the forms and .adapted to receive the sheet'steel piling which is to be driven toform the walls. Sheet steel piling usully has one male edge and one female edge, the two edges being interlocked by driving` the piling and one of the anchors is preferably provided with a male edle and the anchors on the other side of the shaft with These anchors are usually formed by cutting a sheet steel pile .in half longitudinally on a tortuous line and the cut portions `of the pile extend through the form (l into the interior thereof where they are secured to reinforcing;` I3 within the fornin which reinforcement is shown as secured to vertical reinforcing rods 13". fr Iter the concrete has been poured into the form, the anchors are solidly and rigidly held.

lifter the shaft 7 has been formed and set, the form 6 is removed and the cylinder 2 is lifted from. position and advance( to another position where it is againfsunli for the purpose of forming another shaft. The shafts are formed successively, followingaround the curve of the coffer, and after all of the shaft-shave heen completed and the cylinders withdrawn, the sheet steel piling 9 is driven to confine the spaces between the successive shafts. The mud, sand or other material contained in these spaces .is then removed. and the space is then completely filled to any desired elevation with concrete, which may be placed in any desirable manner. rThe concrete ina-y be placed with a treinic, without unwatering the conlined space, or a canvas stockin` of the size and shape of the confined space may be fitted into the space and the concrete poured into the stocking, which would prevent washing` out of the concrete. rlhese walls are built up to a point above the water level and when they have been completed, there is produced a `great concrete cylinder which has been built up underwater in vertical sections and which forms a stable, watertight Colfer. The area within the coffer isthen excavated to the desired grade and, the bottom of the area may be sealed with concrete placed with a tremie, before the water is pumped out. Any desirable structure may now be built wit-hin the coffer and, when it is desired, the coffer may form part of the structure.

The invention of course is not limited to a coder having walls formed in a cylindrical shape since it is obvious that the invention may be applied to a coffer having inclined walls or a coffer in which the walls are not curved but form straight sides which are joined together to inclose a given area. The walls 14, connecting the shafts, are preferably curved on the same curve of the axis of the shafts, but this is not necessary, since when desired the connecting walls may be given any desired curvature to meet the requirements of the situation. When it is desired, piles 16 may be driven in the confined area within the coffer, before the sealing layer of concrete is placed therein.

I claim: g

l. A coffer comprising aplurality of spaced concrete shafts formed in situ. and

Ysinroundingg` the area to be dewatered, a

pair of elongated vertically disposed anchors projecting` from each side of each shaft, sheet steel piling connectingthe anchors on one side of each shaft with the anchors on the adjacent side of the next shaft whereby the shafts are connected by a pair of spaced walls and a filling of concrete in the spaces enclosed by the walls.

V2. The method of buildinga coffer which comprises sinking` a shell to the established grrade, removing the material from the in terior of the shell, placing a shaft form in the shell, lillini,T the form with concrete, forming;` a secondshaft in the same manner, confining a space between the two shafts,

lil() lill) removing the material from the confined space and lilling the space With concrete.

The method of building a @offer which comprises sinking a shell to the established grade, removing the material from the interior of the shell, placing a shaft form in the shell7 illing the form with concrete, removing the shell, forming a second sha'l't in the same manner, removing the forms 'from the shafts, confining a space between the shafts, removing the material from the space and filling the space with conci'ete.

l. The method of forming a coller wall comprising, forming spaced concrete shafts in situ and embedding two pair of attaching members in the concrete of each shaft, positioning sheet piling in two rows between said shafts and connecting the same to corresponding attaching members, and illing in the space bet-Ween adjacent shafts to form substantially a continuous Wall.

5. The method of forming a subaqueous Wall comprising forming a concrete shaft in situ and embedding a pair of anchoring members embedded in the concrete, attaching form members to said anchoring niembers, and filling the forms with concrete.

In testimony whereof I have hereunto set my hand.

BEN C. GERWICK. 

